Re-key FM auto-memory from checkout-path to agentId (root cause of orphan-on-path-change)

Context

The root-cause lane behind #13190 (which reconciles the symptom). Surfaced while deciding the #13190 archive policy (V-B-A'd this session).

The Problem (V-B-A'd at dev)

FM auto-memory is checkout-path-keyed — removeAgentRepo's own docstring (ai/services/fleet/removeAgentRepo.mjs L28-29) states it directly: "the Fleet Manager's auto-memory is checkout-path-keyed — so deleting a path orphans memory keyed on it." The fragility: rows orphan on any path change, not just removal. The empirical ~1281-orphan precedent that motivated #13190 came from a path change, not an agent removal — which is the tell that the key itself is wrong, not just the removal flow.

Checkout-path is an unstable key: it changes on managed-root migration, repo-slug change, or any re-provisioning. agentId (the Fleet Manager agent identity, already the canonical key in MemoryService — metadata.agentIdentity + the AUTHORED_BY edge) is stable across all of those.

The Fix

Re-key auto-memory from checkout-path to agentId:

• Write path: key new auto-memory rows by agentId (derive once at write, not the volatile path).
• Migration: map existing checkout-path-keyed rows → agentId (the checkout→agentId derivation already exists via deriveAgentRepoPath / inspectAgentRepo), re-key in place.
• Result: a path change no longer orphans anything; #13190's reconcile becomes a thin safety net rather than a load-bearing cleanup.

Acceptance Criteria

• New auto-memory rows are keyed by agentId, not checkout-path.
• A migration re-keys existing checkout-path rows to agentId (idempotent; archived rows preserved).
• A path change (re-provision under a new path) orphans zero rows (the regression guard).
• #13190's archive-reconcile still runs as a safety net (no regression).

Out of Scope

• The #13190 archive-on-removal reconcile (the symptom lane — ARCHIVE policy decided: set archivedAt + orphanedByRepoRemoval).
• The archiveMemoriesForCheckoutPath MC primitive (a #13190 dependency).

Related

• Root-cause of: #13190 (symptom reconcile). Touches: removeAgentRepo (#13187), the FM remove facade (#13338), MemoryService (the keying). MC-owned (the keying + migration are Memory-Core decisions).

Live latest-open sweep: gh issue list --search "auto-memory re-key / keying" → only #13190 (the symptom) at 2026-06-21T20:59; no root-cause re-key issue.

Origin Session ID: 80932414-00dc-4d2e-96e6-d0bcf1529733

Retrieval Hint: query_raw_memories("FM auto-memory re-key checkout-path agentId root cause orphan path-change stable key #13190 symptom")